This invention relates to a process for the preparation of hydrolytically stable cationic coating compositions, to the coating compositions prepared by said process and to the use thereof, particularly as aqueous thermosetting coating compositions for application via electrodeposition.
European Patent Application EP No. 0127915 discloses aqueous thermosetting coating compositions based on polyaddition products of defunctionalized multifunctional polyglycidyl ethers, diglycidyl ethers and selected amino group-containing compounds. Such defunctionalized polyglycidyl ethers are those having on average n epoxy groups per molecule, wherein 1&lt;n&lt;2. They comprise the reaction products of multifunctional polyglycidyl ethers having on average x epoxy groups per molecule, wherein x&gt;2, and (x-n) mol of a monofunctional phenol per mol of multifunctional polyglycidyl ether. The coating compositions, based on combinations of these polyaddition products with co-curing resins, when applied by electrodeposition and after stoving, yield coatings which have very good flow and flexibility properties as well as a good resistance to sterilization. This combination of performance properties makes them very suitable for use as the internal lining of cans for many different applications. However, when used as the internal coating of cans for applications where taste performance requirements are very critical, such as in certain beverage cans, some of these coatings failed to pass the most severe taste performance tests. Thus the taste performance properties of such coatings leaves room for further improvement. It is therefore an object of the present invention to improve the taste performance properties of these cationic coating compositions, while maintaining the high level of the other performance properties.